OK, flame me but I think this is all a fuss over nothing.

How big a problem is this distortion - really? Is it really and truly noticeable to anyone other than those tying ever so hard to hear it?

I love my XP-60 - so do tens of thousands of 60 - 80 owners around the world.

In my (amateurish and ill-informed) opinion this is a theoretical problem, not an actual one.

My ten bob's worth, anyway.

Martin